1. Field of the Invention
The present invention relates to an inkjet head actuator and a manufacturing method of the same, and more particularly, to an inkjet head actuator including a thin film piezoelectric body and a vibration plate to ensure large vibration displacement and a low driving voltage.
2. Description of the Related Art
In general, an inkjet head is a device for printing an image of a predetermined color on a printing material by ejecting fine droplets of a printing ink onto a desired location of the printing material such as paper or textile. This inkjet head is classified variously according to the ink ejection method. One type is a heat-driven inkjet head which generates bubbles in ink using a heat source and ejects the ink by an expansion force of the bubbles. Another type is a piezoelectric inkjet head which ejects ink by a pressure applied to the ink resulting from transformation of a piezoelectric body.
In the piezoelectric inkjet head, an actuator refers to a configuration encompassing a chamber plate 101, a vibration plate 102, a piezoelectric body 104, and upper and lower electrodes 105 and 103, as shown in FIG. 1, while excluding a restrictor, a reservoir, a chamber and a nozzle. However, the actuator may be configured without the chamber plate 101. In this case, the piezoelectric body 104 is disposed between the upper electrode 105 and the lower electrode 103. Also, a bottom surface of the lower electrode 103 is joined to the vibration plate 102. Also, a bottom surface of the vibration plate 102 is joined to the chamber plate 101. In this piezoelectric inkjet head, the actuator is a significant element in determining ink ejection capability of the inkjet head, and should advantageously ensure large vibration displacement upon application of a voltage and a lower operating voltage. To this end, the piezoelectric body 104 and the vibration plate 102 need to be thinned as much as possible.